1. Field of Invention
This invention relates to the propulsion system's of lever propelled bicycles.
2. Background of the Invention
In the bicycle industry, there are the alternative types of bicycles that are propelled by lever machines, which pivots back and forth, instead of in the conventional manner of the rotational of crank arms. What the Lever Enhanced Pedaling System (LEPS) has to offer is low pedaling resistance. Low pedaling resistance occurs when there is no significant upward force from the bicycles pedaling components, resulting in an increase in torque while pedaling this type of bicycle. The upward force from a conventional bicycle comes from the crank arm being in the 90 degree or near vertical position, resulting in the area of applied force (pedals) coming closer to the fulcrum (crank axle) horizontally distance wise. Thus, the closer the area of applied force is to the fulcrum, the greater the effort there must be to propel the bicycle forward. So one may experience a fluctuation of pedaling force when pedaling a conventional bicycle, after noticing that when the forward pedal of the bicycle is pressed downward while in its 180 degree or near horizontal position, pedaling torque increases. This is because the area of applied force is the most furthest away from the fulcrum. The LEPS, however, maintains its area of applied force at a distance from its fulcrum, that is more constant or in a near linear path (FIG. 2) while the pedals are being pressed downwards. This linear path is not exactly linear, but slightly curved. This curved path is sufficient enough to maintain a near constant level of torque while pedaling this bicycle. This constant level of torque establishes a mechanical advantage that is above that of all conventional bicycles using a rotational pedaling configuration.
Mechanical advantage is not limited to just torque per pedal, but also must include range to torque ratio. In order for a pedaling system to have more mechanical advantage, it must have more torque with equal amount or more pedaling range than the conventional bicycle. This is why the LEPS has adopted a propulsion system with a roller chain that is configured to pull the rear wheel drive component into rotation around the smallest diameter possible. The essential part of this rear wheel drive component that the roller chain pulls is a cylinder 14 (FIG. 4 & FIG. 6) or drive cylinder, which is closely occupied by the axle 18 of the rear wheel. Thus, the sprocket was omitted from this mechanism, because it would reduce the pedaling range of the bicycle due to the nature of its large diameter. This means that the roller chain 2 would rotate the cylinder 14 around the axle 18 of the rear wheel, after it was wrapped around said cylinder (FIG. 6), which would rotate the rear wheel connected to the cylinder.
Experiments were conducted on such a mechanism, which resulted in a sufficient amount of pedaling range, but then a problem remained which had to be solved. When the chain 2 wrapped the cylinder 14 and itself, torque would increase as well as the diameter of the chain's circular position, generating an uneven amount of torque. Thus, a new chain arrangement was invented in order to prevent the chain from wrapping around itself, while facilitating the chain 2 wrapping around the drive cylinder 14 at least 1¾ times. This 1¾ wrap around chain configuration allowed for 1¾ wheel revolutions per pedal, which exceeds performance standards for single speed bicycles. In order for this wrap around chain system 2 to actually work, it would be essential to cut the length of the chain 28 to or near to the circumference of the drive cylinder 14 so it could be wrapped around the drive cylinder 14, while the ends of the chain 28 are almost touching each other. The first end of this chain 28 would have its first chain bore occupied by a steel rod 32, which would be used to fastened this end of the chain to a radial drive disk 24 connected to the drive cylinder 14 by the welding process. Then, the second portion of the chain 30, which continues to wrap around the drive cylinder 14 would be offset in connection to the former chain portion 28. This offset connection would be at the last chain link bore of the first chain 28 mentioned and the first chain link bore of the second chain 30. Both bores would be aligned with a spacer 34 between them the latter's bore aligned as well. Then a steel rod 48 would occupy these bores and be used to fastened the assembly 2 together (FIG. 5B). The spacer 34 would act as a means to prevent the roller chain pins (28 & 30) from colliding with each other while the chain 2 is being wrapped adjacently around the drive cylinder 14. The other end of the second chain member 30 would be connected to the lever machine 46, around the load point 4 and this load would be pulled in a rearward direction. The LEPS's lever machine 46 and reciprocal system 56 has a mechanical design that would make the LEPS wrap around chain propulsion system original and produce new mechanized results due to such an arrangement. For example, the component in U.S. Pat. No. 4,574,649 awarded to Seol has a cable 7 that moves through the grooves of pulley wheels 13 and each end of the cable is attached to a separate roller chain. The LEPS has a cable 8 that moves through four pulley wheels (10 & 22) and each end is directly connected to a radial drive member 26 as well as it's member drive cylinder 14, but not separate roller chains 28. Furthermore, each roller chain 28 is connected to a separate radial drive member 24 that are welded to member drive cylinders 14. This new arrangement results in a drive radius that is smaller than most lever propelled bicycles in its field and this smaller drive radius allows each roller chain assembly 2 to rotate the connected rear wheel at more revolutions per pedal than if a sprocket was used. Each reciprocal cable 8 pulls and rotates it's connected drive cylinder 14, while reeling in it's member roller chain assembly 2.
Another feature that distinguishes the LEPS from Soel's invention is the length of the lever machine 46. The LEPS has the area of applied force (pedals) 42 distance to the load (roller chain connection) 4 more than twice the distance than the load is to the fulcrum in its highest gear and this is why such a mechanized configuration will have more mechanical advantage. Other different features include a reciprocal cable system 56 that moves inside the bicycle's frame 40 instead of on the outside of it. Furthermore, the way the roller chain 30 is connected to the load bolt 4 on its member lever machine 46 is different than the prior art. The chain 30 is partially wrapped around the load bolt 4, while partially overlapping it self (FIG. 5A) in order to adjust tension on the chain 30 after calibrating the reciprocal cable system 56 connected to the drive cylinder 14. Each reciprocal cable end 8 is designed to alternately wrap its member transmission chain assembly 2 while it is being pulled. After tension in the reciprocal cable 8 is established, tension in the roller chain must be established by wrapping the roller chain 2 around the drive cylinder 14 that is not wrapped with the reciprocal cable 8. Then tension on the roller chain 2 should be established by pulling the roller chain 30 around the load bolt 4 until it is tight and bolting the overlap of the chain 30 to its longer portion by inserting bolts 16 (FIG. 5A) in aligned chain link spaces. This connection must then be fastened in place with nuts. The other side of the reciprocal cable 8 should be wrapped around the drive cylinder 14, but the roller chain 2 should be unwrapped around member drive cylinder 14 and tension on this roller chain 2 should be established like the former mentioned roller chain. The reason why tension on the cable 8 and roller chains 2 are important is because tension on such components will allow maximum forward travel per pedal when they engage the drive cylinder 14 or when a rider pedals the bicycle.
The Propulsion mechanism for lever propelled bicycles (U.S. Pat. No. 4,630,839) awarded to Seol has many differences when compared to the LEPS's chain wrap around system that would establish the latter system as original offering novel results. The device invented by Seol has separate transmission chains the pull it's radial drive member in a forward direction in contrast to the LEPS's system, which pulls its radial drive member in a rearward direction. The rearward pull system gives its lever machine more design options, because it lever machine 46 can be lengthened beyond the axle 18 of the rear wheel. This design option allows the LEPS's lever machine 46 to be stretched rearward to increase mechanical advantage without compromising standard wheel base length or ergonomic pedal position. Further differences between the former mentioned invention and the LEPS is the position of propulsion chain engagement. The chain of the former invention has two propulsion chains that engage symmetrical radial members (12 and 12a, FIG. 2) that are connected by the same axle. This chain engagement is close to either pedal when a pedal is in its peak position. This position may be close enough to snag the hem of a rider's pants if it were caught in this engagement. The propulsion chain engagement of the LEPS is within the rear tube of its frame 40, thus making it free from entangling a rider's clothes.
The Lever driven bicycle (U.S. Pat. No. 5,988,662) awarded to Staehlin has various distinctions when compared to the LEPS's system that makes the latter new and unique. The Lever driven bicycle has its fulcrum on the axle of the rear wheel, while the fulcrum 44 of the LEPS is connected to the frame 40 of the bicycle behind the axle 18 of the rear wheel. Having a fulcrum 44 connected to the rear frame 40 has the advantage of easy rear wheel removal for maintenance purposes. After the axle 18 of the LEPS is removed from the rear wheel, the rear wheel can be dropped out for repairs. The Lever driven bicycle would be difficult to repair because the rear reciprocal system would be attached to its lever machine, while the axle is connected to the bore of each symmetrical lever machine composing the fulcrum. Because the axle of the rear wheel is directly and indirectly connected to the frame of this lever propulsion system, is why it would be very difficult to remove this wheel for maintenance. This is why the LEPS's wrap around chain propulsion system will have an advantage over such a system. Furthermore, the reciprocal system of the Lever driven bicycle is too close to the fulcrum. This closeness would generate multiplied pressure from the effort spread out from the longer rigid mass of material composing the lever machine leading the fulcrum. Thus, this pressure may cause the components of the reciprocal system to break down earlier than components of the average bike. The LEPS has a reciprocal system 56 that is further away from its member fulcrum 44, thus the system would last longer.